I have a Drupal site with many modules enabled (CCK, views, rules, etc). The site will be used by several hundred people so I want fast page loads and the server to be able to withstand a large load. Everyone using the site is going to be a authenticated user so modules like Boost aren't going to help. The server's really good, dual-core and 6 gigs of RAM. I've installed APC, and it is awesome, but I have no idea how to put the rest of all this RAM to use.
I was thinking of using Authcache but afraid because a) I never want a user to see old content and b) my site has many views and pages which are specific to each particular user. I am now thinking more towards Memcached, but have no idea where to start.
So I am turning to all your expert advice as to how to put all this RAM to use.